Electric furnace



June 15 1926. if 1,588,611

T. A. REID ELECTRIC FURNACE Filed June 25, 1921 IFJ- Aff e f2y4 /7 WITNEssl-:s: V /7 INVENTQR TORNEY Patented .lune 15, 1926.

UNITED STATES PATENT OFFICE.

THOMAS A. REID, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC FURNACE.

Application led .Tune 25,

My invention relates to electric furnaces and particularly to electric-resistance furnaces and it has for its object, to provide a relatively simple resistor-supporting means for an electric furnace.

In practicing my invention, I provide a plurality of pairs of relatively small grooved cooperating refractory resistor-supporting members located around the periphery of the furnace chamber and means for maintaining the members in their proper operative positions in said furnace.

In the single sheet of drawings;

Figure 1 is a view, in vertical lateral cross-section, of an electric-resistance furnace comprising the device embodying my invention;

Fig. 2 is a view, in longitudinal vertical y cross-section, on the line II-II of the furnace illustrated in Fig. 1;

Fig. 3 is a view, in side'elevation, of a pair 'of resistor-supporting members, a set of retaining members and a portion of the resistor element, and

Fig. 4 is a view, in end elevation, of the members illustrated in Fig. 3.

An electric 'furnace 5 comprises a suitable metallic framework or casing having a bottom portion 6 and a stop portion 7 Heatinsulating bricks or blocks 8 are located inside of the casing parts 6 and 7, to provide a-furnace chamber 9 of any suitable or desired contour and dimensions. As illustrated in the drawings, the furnace chamber 9 is substantially cylindrical in contour, as it is desired to locate therein a substantially cylindrical rotatable metal drumy (not shown) in which material to be heat treated may be placed.

. Bearing members 10 are provided at each end of the furnace 5 to support the rotatable drum. The top casing 7, together with all of the other parts operatively associated therewith, may be removed from the bottom part of the furnace to permit of removing and replacing the rotatable drum, suitable lifting means (not shown) being provided. If desired, the upper part of the furnace may be hinged to the lower part to permit of turning the upper part out of the way to permit of removing and replacing the ro-4 tatable drum.

An inner metallic lining 11 is provided to conform to the inner wall formed by the blocks 8.

1921. Serial No. 480,261.

A plurality of pairs of retaining members in the form of angle bars'12, are located in spaced-apart relation and are suitably secured to the metallic lining 11. The pairs of bars 12 are located in longitudinally spaced relation and a refractory member 13 is placed between the bars of each pair. The members 13 are substantially rectangular in cross section, each being provided with a substantially semi-cylindrical groove 14 in its outer face, the grooves being so located as to 'extend longitudinally of the furnace.

A second set of retaining members, composed of spaced angle bars 15, is located inside of the pairs of outer retaining bars 12. An inner metallic band 16 operatively engages the inner surfaces of the members 15 and is suitably secured thereto, either by means of bolts or by welding, to maintain the members 15 in spaced-apart relation.

Resistor-supporting members 13, equal in number to those located between the outer retaining members 12, are placed between the members 15. The two semi-cylindrical grooves 14, in each pair of members 13 cooperate to form a substantially cylindrical groove in which a resistor member 17 may be located.

The resistor member 17 comprises a metal bar or rod of relatively large cross-sectional area having a plurality of endconnected, substantially straight, convolutions. As the sets of retaining members and the supporting members are spaced apart relatively large distances, it is necessary that the crosssectional area of the resistor member 17 be large enough to cause the resistor lto be substantially self-sustaining between the supports. The ends of the resistor 17 may be brought out at the ends of the furnace through suitable insulating tubes 18 to terminal members 19,(located on the outside of the furnace structure.

In order to provide suitable supports for the outer retaining members 12 and the inner retaining members 15 and 16, longitudi- It is apparent that the lateral width of the members 13 may be varied to permit of changing the number of pairs of resistorsupporting members which may be employed in the furnace, this change carrying with it a corresponding change in the number of convolutions of the resistor member itself. By this means, aswell as by changing the cross-sectional area of the resistor, it is possible to vary the resistance of the resistor within any suitable or desired limits.

The heating element comprising the resister member 17, the resistor-supporting members 13 and the outer and inner retaining members may be assembled substantially as follows: referring particularly to the bottom half of the furnace, the inner retaining'members 15 and 16 and the supporting members 13 operatively engaging the same, may be assumed to have been removed from the furnace. The proper number of supporting members 13 may be placed between the cooperating pairs of retaining members 12, being held t.in place by tlre formed resistor 17 the convolutions of which may be placed in the semi-cylindrical grooves 14. The inner set of supporting members 13 may then be placed in position, being temporarily held in place by the resistor member 17 engaging the groove 14 therein. It may be noted that the number of pairs of members 13 is determined more particularly by the number which can be placed in the inner set of retaining members. The assembled members 15 and 16 may then be placed in operative position relatively to the inner side of the supporting members 13 and the outer ends thereof suitably secured to the members 2() and 2l. The upper part of the furnace may be swung on its hinges until it is in substantially an inverted position when the same method of assembly of the heating element may be followed.

It may be noted that the device embodying my invention provides a relatively simple and easily installed i resistor-supporting means comprising a plurality of pairs of relatively small grooved cooperating refractory members, a plurality of sets of which are located in spaced relation around the periphery of the furnace chamber.

Various modifications may be made in the device embodying my invention without departing vfrom the spirit and scope thereof and I desire that only such limitations shall be placed thereon as are imposed by the prior art or are specifically set forth in the appended claims. v

I claim as my invention:

1. In an electrically heated furnace, the combination With a casing, of a plurality of engaging pairs of refractory resistor-supreseau ing members supported by said retaining members, and a resistor element supported py and between the pairs of supporting memers.

3. In an electrically heated furnace, the combination with a casing, of a plurality of setsof retaining members, the co-operating members of each set being spaced longitu-v dinally of said furnace, a plurality of radially-alined pairs of refractory resistor-supporting members supported by said retaining members, and each supporting member having a groove in its contacting face, and a resistor element extending through the grooves between the pairs of refractory members.

4. An electrically heated furnace comprising a casing, a plurality ofsets of spaced retaining members extending around the inner periphery of said casing, a plurality of pairs of co-operating radially-alined refractory supporting members located in said sets of spaced retaining members, each of said supporting members having a transversely extending groove inits opposing and contacting face, and a resistor-element located in the opening formed by said grooves and extending between saidsetsof members and directly supported thereby.

5. An electrically heated furnace comprising a casing, a plurality of pairs of oppositely spaced outer retaining members extending around the inner periphery of the casing and secured thereagainst, a plurality of pairs of oppositely spaced retaining members and an inner band located inside of said outer retaining members, a plurality of refractory supporting members located between the spaced retaining members of each of said pairs, each supporting member having a groove in its opposing face anda resistor element located in the opening formed by said grooves and extending between said pairs of retaining members, said resistor element being adapted to maintain said opposing refractory members in proper circumferential a-linement.

In testimony whereof, I have hereunto subscribed my name this 20th day of June THOMAS A. REID. 

